This invention relates in general to wheel trucks for steerable platforms such as skateboards.
Steerable platforms such as skateboards and roller skates have heretofore employed wheel truck designs in which wheels are mounted on a solid axle frame or axletree which in turn is carried below the platform on an inclined steering shaft. The axletree is connected at another point with the platform by a rubber bushing which permits the axletree to pivot about the shaft for steering action.
The prior art wheel truck designs described above have a number of limitations and disadvantages. In a typical truck design the axletree is attached to a steering shaft through a non-yielding connection so as to pivot about a fixed axis. The non-yielding nature of the connection at this critical load point results in a part of the shock forces being carried directly through the wheel truck to the platform, which can result in failure of the component parts. Further, any attempt to vary the angular orientation of the axletree for adjusting the turning radius tends to cause the pivot elements to bind because of the fixed pivot axis connection. Another problem caused by the fixed steering axis connection is that the geometry of the parts causes the wheel truck frame when in operation to exert a large force on the lower support bushing which in turn tends to create undesirable oscillations or wobble.